We propose to continue investigating the means by which injuries heal reaching specifically into areas in which repair is controlled so as to find means by which repair can be hastened when it is inadequate and be suppressed when it reaches the point of constricting scar. We intend to pursue further our own basic discoveries that wound strength gain (collagen synthesis) can be slowed by oxygen starvation and accelerated beyond normal by providing excess oxygen. We also intend to follow our potentially very important discovery that wound infections are partly preventable merely by supplying 40% breathing oxygen by determining the mediator of the effect which is probably the white cell. We will continue to pursue the nutritional requirements of normal repair and will start to investigate the signals by which repair is started and stopped. Until separate support can be obtained, we will continue to investigate the means by which liver regenerates after large portions of liver have been injured or removed. In the coming year, we will investigate the gaseous environment of healing bone, the pO2 and pCO2 of human wounds in severely traumatized patients and the role of growth hormone in stimulating fracture repair.